Shape-changing support, such as for seating

ABSTRACT

A back construction for a seating unit includes a plastic back shell having a flexible lumbar region and configured to support a seated user&#39;s torso, and a lumbar adjustment mechanism in the form of a pleated bladder attached to a face of the flexible shell so that when the pleated bladder expands in a thickness direction and simultaneously shortens in a vertical/longitudinal direction, the back panel is flexed to a different more curved shape in its lumbar region. The lumbar adjustment device can be removably or permanently attached to the back shell, and the back shell can be pivotally attached to a rigid back support at one or more locations.

BACKGROUND

[0001] The present invention relates to seating units providing ashape-changing support for a seated user, and more particularly relatesto a back having a flexible lumbar region and lumbar adjustmentmechanism that constricts to change a shape of the lumbar region.However, the present invention is not believed to be limited to onlybacks.

[0002] Many modern chairs often include a lumbar support placed on afront surface of a back support or integrated into a chair back. Thelumbar support forms a new shape chosen to provide increased usercomfort. Sometimes the lumbar supports are incorporated into the back,and sometimes they are made vertically adjustable. However, many ofthese constructions result in a back construction that is noticeablythick and heavy in appearance, which is undesirable in many chairdesigns. Further, it is preferable that the adjusting mechanism notmerely be an extra device with multiple pieces assembled onto a back,but instead that it be well integrated into the back. Also, it ispreferable that the adjustment device be multi-functional and providemore than just adjustment to the lumbar region of a back, and that it bedurable, long-lasting, and low cost. Still further, it is preferablethat any adjustable lumbar mechanism be easy to adjust and alsointuitive to adjust and use, but that it use few pieces.

[0003] Most chairs last a long time. It is desirable to provide anadjustable lumbar mechanism that can be sold as an option alreadyinstalled on a seating unit, or that can be sold and installed after theoriginal sale of the chair (i.e. field-installed), and/or that can beeasily removed for cleaning and/or replacement, and yet that is secureand visually blends in well with the aesthetics and appearance of thechair.

[0004] Accordingly, an apparatus is desired having the aforementionedadvantages and solving the aforementioned disadvantages and problems.

SUMMARY OF THE PRESENT INVENTION

[0005] In one aspect of the present invention, a back construction for aseating unit includes a flexible back panel configured to support aseated user's torso, and a bladder attached to the flexible back panelso that when the bladder expands in one direction and simultaneouslyshortens in a different direction, the back panel is flexed to adifferent shape.

[0006] In another aspect of the present invention, a back constructionfor a seating unit includes a rigid back frame, a flexible back panelattached to and supported by the back frame at spaced-apart points, anda constrictable energy mechanism operably coupled to the flexible backpanel at spaced-apart locations so that, when the energy mechanism isenergized and constricts, the back panel is flexed to a different shape.

[0007] In still another aspect of the present invention, ashape-changeable component for a furniture unit includes a flexibleplastic panel having a face, and an inflatable member operably attachedto the plastic panel and lying on the plastic panel so that when theinflatable member expands in one direction and simultaneously shortensin a different direction, the plastic panel is flexed to a differentshape.

[0008] These and other aspects, objects, and features of the presentinvention will be understood and appreciated by those skilled in the artupon studying the following specification, claims, and appendeddrawings.

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIGS. 1-3 are front, side, and top views of a back constructionincluding a flexible shell and a removable back covering incorporatingan air bladder adjustment mechanism, the adjustment mechanism beinginflatable to cause a shape change in a lumbar region of the shell;

[0010]FIG. 4 is an enlarged side view of a bottom portion of the backshell and bladder in the circled area IV in FIG. 2, the back frame beingremoved for clarity;

[0011]FIG. 5 is a front view of a back cover assembly including theadjustable lumbar support mechanism shown in FIG. 1;

[0012]FIG. 5A is a cross section taken along line IV-IV in FIG. 4, theair bladder being inflated and in an energized state;

[0013]FIG. 5B is a cross section similar to FIG. 4A, but the air bladderbeing uninflated and in a relaxed state;

[0014]FIGS. 5C and 5D are enlargements of the circled areas VC and VD inFIGS. 5A and 5B;

[0015]FIGS. 6 and 6A are front and side views of a modified backconstruction including a permanently-attached inflated/energized lumbaradjustment mechanism;

[0016]FIG. 6B is a side view similar to FIG. 6A, but with the bladderdeflated;

[0017] FIGS. 7-8 are perspective and side views of another modified backconstruction including a permanently-attached inflated/energized lumbaradjustment mechanism.

[0018]FIG. 9 is a side view similar to FIG. 8, but with the bladderdeflated;

[0019]FIG. 9A is a fragmentary perspective view of an inside of the rearupright showing details of the slide mechanism in FIGS. 7-9; and

[0020] FIGS. 10-12 are views of another modified back construction, theviews of FIGS. 10-12 being similar to FIGS. 7-9 above.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0021] The present illustrated back construction 20 (FIG. 1) is usablein the environment of an office chair having a castored spider-leggedbase, a seat, and an underseat control for pivoting the back 20 and seatwith a synchronous motion upon recline of the back 20. A more detaileddescription of one such chair can be found in U.S. Pat. No. 5,975,634,issued Nov. 2, 1999, entitled CHAIR INCLUDING NOVEL BACK CONSTRUCTION,the entire contents of which are incorporated herein by reference.Nonetheless, it should be understood that the present invention iscontemplated to be adaptable for any seating unit or other furnitureutilizing a flexible support.

[0022] The illustrated back 20 of FIG. 1 includes an arching back frame25, and a sheet-like flexible plastic back shell 26 pivotally attachedto the back frame 25 at top and bottom locations 33 and 34 (FIG. 2). Thegeneral operation and interaction of back shell 26 and back frame 25 aredescribed below in sufficient detail for an understanding of the presentinvention, but details can be found in U.S. Pat. No. 5,975,634, if thereader desires this information.

[0023] The back shell 26 (FIG. 1) has a “potato chip” like shape, withits front surface having a horizontal cross section that is forwardlyconcave and a vertical cross section that is forwardly convex. The backshell 26 has a flexible lumbar region 27 connecting stiff thoracic andpelvic regions 28 and 29. The lumbar region 27 includes a pair ofvertical edge strips 30 and 31, and a plurality of horizontallyextending strips 32 separated by slots extending between the edge strips30 and 31 to define a flexible lumbar area. A belt bracket 35 extendsalong a lower edge of the back shell 26, and includes forwardlyextending flanges 36 that define the bottom pivots 34. In U.S. Pat. No.5,975,634, a biasing device is provided on the lower pivot to bias thelumbar region forwardly. In the present construction, a muscle-like airbladder energy mechanism is provided in a cover assembly 37, asdescribed below, for changing a shape of the lumbar region 27 of theback shell 26.

[0024] The cover assembly 37 (FIG. 5) includes a sock-like top section38 sewn of upholstery or fabric to define a downwardly-facing pocket 38′that fits mateably over a top edge of the back shell 26 (FIG. 1) andonto the thoracic region 28. A center section 39 of the cover assembly37 extends downwardly over a center area of the lumbar and pelvicregions 27 and 29. A stiff strip 40 is sewn along a bottom edge of thecenter section 39, and is shaped to fit mateably into a recess 41′ (FIG.4) in a bottom edge of the back shell 26 with a zipper-like motion,where it is frictionally retained. Fasteners can be used for additionalretainment, if desired. It is contemplated that other releasable orpermanent top and bottom attachment devices can also be used.

[0025] A constrictable energy mechanism 39′ in the form of a pleatedbladder is attached to the center section 39 (FIG. 5). The energymechanism 39′ extends vertically downwardly onto a front panel of thetop section 38. The energy mechanism 39′ comprises a laminate (see FIGS.5C and 5D) with a non-stretchable first inner layer 41 providingstrength and flexibility (such as nylon fiber, woven fabric, or thelike), and second and third layers 42 and 43 that are air impermeable(or fluid impermeable) (such as rubber or elastomer), and that define abladder 45 having horizontal cavities 46 (also called “sub-bladders”)for receiving air (or other fluid). (It is noted that instead ofhorizontal cavities, the cavities can be round, oval, or other shapes.)As illustrated, a fourth layer 44 similar to layer 41 is provided. It iscontemplated that a variety of different materials can be used to formthe bladder, and further, that different inflating fluids can be usedother than air.

[0026] In the illustrated arrangement, the first and fourth layers 41and 44 are the outermost and innermost layers, respectively, and arenylon sheets that allow flexibility but that provide good strength indirections within the sheets. For example, 200 denier nylon wovensheeting will work for this purpose. The second and third layers 42 and43 are elastomeric film, such as ether-based urethane, having an 85Durometer. The layers 41-44 are bonded together by radio frequency (RF)welding or other bonding technique around their perimeter to define abladder. The layers 41-44 are further bonded together at multiplehorizontal pleats 47 (FIG. 6) that extend partially horizontally acrossthe bladder area to subdivide the bladder into multiple discretehorizontally-extending sub-bladders 46 between the pleats. Thesub-bladders 46 are connected at edges by air-communicating edgepassages 48. An air line 49 is attached to the bladder 45, and a handpump 50 is attached to the air line 49. The pump 50 can be located atdifferent locations. As illustrated, the pump 50 (FIG. 6A) is locatedalong a side of the seat 23, but it could also be located under anarmrest 51 of the chair, under the seat 23, on the back 20 such as at abottom or at a top in a headrest area, on a base of the chair, or atother locations. The air pump 50 includes a flexible bulbous member 51that can be repeatedly manually squeezed to pump air through the line 49into the bladder 45, and further includes a valve 52 that can be openedto release air from the bladder through line 49 to atmosphere. It iscontemplated that a powered air pump, such as a battery-powered pump,could be used instead of a manual pump. Further, a flowable fluid otherthan air could be used, such as a liquid pumped from a container underthe seat.

[0027] When deflated or uninflated (see FIGS. 5A and 5C), theillustrated energy mechanism 39′ has a thickness of about 5 mm, and thepleats 47 are spaced vertically apart about 15 mm to 20 mm, or morepreferably about 19 mm apart. When inflated, each sub-bladder 46 expandsfrom its “linear” shape toward a cylindrical horizontal shape (see FIGS.5B and 5D), such that a gross vertical length of the cover assembly 37shortens. If the back shell 26 had a flat horizontal cross section, thisshortening of the bladder would cause the back shell 26 to bend toward amore planar condition. However, since the edge strips 30 and 31 of theback shell 26 are forward of the sub-bladders 46, the illustrated backshell 26 actually flexes toward a more curvilinear shape as thesub-bladders 46 are inflated. (Compare FIG. 5A, which has a deep concaveshape shown by dimension T₁, and FIG. 5B, which has a shallower concaveshape shown by dimension T₂.) Notably, the total surface length of theouter and inner layers 41 and 44 always stays the same. As a result,when the bladder 45 is inflated, it reacts much like a human muscle andshortens. For example, the spacing between pleats 47 changes from adimension “X” of about 19 mm (FIG. 5D) to a vertical spacing of about 13to 15 mm (dimension “Y”, FIG. 5C) (depending on the amount of air pumpedinto the bladder 45).

[0028] To operate the present invention, the chair 21 is originallyprovided with the air bladder 45 not inflated. In this condition, theback shell 26 has a predetermined curved shape, as determined byparameters of the chair 21. The cover assembly 37 lies generally flatagainst the back shell 26 and provides a small amount of comfort on afront of the back shell to a seated user. As air is pumped into thebladder 45, the sub-bladders 46 begin to inflate. This causes thebladder 45 to shorten in a length direction. In turn, the back shell 26is stressed as the bladder 45 shortens and the edge strips 31 and 31resist shortening. This causes the back shell 26 to change its shape andflex toward a more curved shape. Also, the air provides some additionalcushioned support to a seated user. When air is released from thebladder 45, the process is reversed, and the back shell 26 moves towarda more linear shape (which is closer to its natural unstressed shape).It is noted that the back shell 26 can be made with enough internalstrength to flex toward the relaxed convex shape as shown in FIG. 5A.Alternatively, a biasing device (such as is illustrated in U.S. Pat. No.5,975,634, previously incorporated by reference) can be used to assistin biasing the back shell to its forwardly convex shape. It is notedthat the illustrated bladder 45 acts both to bias the back shell 26 to amore concave shape, but also combines with the back shell 26 to act like(and produce lumbar support forces similar to) a stiffer back shell (26)(e.g. a back shell made of stiffer material or made with a thickerdimension).

[0029] It is noted that the air in bladder 45 provides both anenergizing system, and also a cushioning action for supporting a seateduser. This multi-functional use has advantages in terms of comfort to aseated user. If the air is heated, the air bladder has furtherfunctional benefits. It is noted that a liquid can be used instead ofair, if desired. In such case, the liquid could be stored in a reservoiranywhere on the chair, such as under the seat, in an armrest, in theback, or in the base of the chair.

[0030] By controlling the vertical spacing of the pleats 47, theoperation of flexing the lumbar region 27 is greatly affected. Forexample, closer vertical spacing of the pleats 47 results in a coverassembly 37 that does not shorten as much as it is filled with air. Inturn, closer spacing of the pleats 47 results in a lumbar adjustmentmechanism that is not able to make as great of a change to the shape ofthe lumbar region 27. Also, the back shell itself can be given differentoriginal concave shapes. Thus, the combined system of the back shell andthe cover assembly is important to overall operation. It is contemplatedthat the bladder 45 could also be positioned horizontally, instead ofvertically, such that its operation causes a horizontal shape change.Still further, a horizontal bladder and a vertical bladder (and/or anangled bladder) can be overlaid or used together to control the backshape in all directions, or the sub-bladder shapes can be dome-shaped,elongated but nonlinear (e.g. L-shaped or Z-shaped), elongated inmultiple directions (e.g. X-shaped or Y-shaped), or any other shapedesired.

[0031] A modified back construction 20A is shown in FIGS. 6-6B, a secondmodified back construction 20B is shown in FIGS. 7-9 on chair 21B, and athird modified back construction 20C is shown in FIGS. 10-12. In theseembodiments, all similar or identical features and components areidentified using the same number as used in back construction 20, butwith the addition of a letter “A”, “B”, or “C”. This is intended toreduce redundant discussion, and not for another purpose. A person ofordinary skill in the art will understand that principles discussed inregard to each embodiment will apply to the other embodiments.

[0032] The modified back construction 20A (FIG. 6) includes a back shell26A, a bladder 45A permanently attached to the back shell 26A, andupholstery (not specifically shown) attached over the bladder 45A andback shell 26A to aesthetically cover the same. More specifically, thebladder 45A includes top and bottom stiff edge sections 54A and 55Aattached with rivets 56A and 57A. The bladder 45A includes pleats 47Asubdividing it into sub-bladders 46A. The remaining components andoperation are identical to or very similar to the back construction 20,and thus the details will not be repeated to avoid unnecessaryrepetition.

[0033] Another modified back construction 20B (FIG. 8) is shown as partof a chair 21B having a castored spider-legged base 22B, a seat 23B, theback construction 20B, and an underseat control 24B for pivoting theback 20B and seat 23B with a synchronous motion upon recline of the back20B. In chair 21B, the back construction 20B includes a back frame 25Bpivoted to the base 22B under the seat 23B at pivot location 24B′ forreclining movement. A biasing device, such as a torsion spring, isattached at the pivot location 24B′. A flexible back shell 26B ispivotally attached to a top of the back frame 25B, but is slidablysupported at its lower edge by a slide member 59B on a lower portion ofthe back frame 25B. When inflated, the bladder 45B causes the back shell26B to flex from its semi-linear shape (FIG. 9) toward a more curvedshape (FIG. 8), causing the slide member 59B to slide upwardly along theback frame 25B. The back frame (or upright) 25B includes a vertical slot60B and a follower 61B attached to a bottom edge of the back shell 26Bis slidably coupled to the slot 60B. Top and bottom ends of the slot 60Blimit flexing of the back shell 26B by engaging the follower 61B as theback shell 26B is flexed. A spring 72B is attached between the follower61B and the top pivot connection 73B on a top of the back frame 25B. Thespring 72B compliments leaf-spring-like edge strips 30B and 31B to causethe back shell 26B to naturally move toward a curved shape.

[0034] Back construction 20B′ (FIG. 9A) replaces the slot 60B andfollower 61B with a channel/track 63B′ formed on an inside of theupright back frame 25B′, and an elongated follower 64B′ that rides inthe channel/track 63B′. Straps 65B′ hold the follower 64B′ in thechannel/track 63B′, and also act as upper and lower limits as theshell-attachment brackets 66B′ engages them.

[0035] Back construction 20C (FIG. 11) is similar to the backconstruction 20B (FIG. 8), except back construction 20C has a one-piecemember 69C with a rigid L-shaped back frame 25C coupled to the backshell 26C by a living hinge 70C. Also, a hook 71C can be provided on thelower leg of the L-shaped back frame 25C. Optionally, hook 71C isdesigned to hookingly engage a flat member, such as a bench or bleacherseat in a football stadium.

[0036] It is to be understood that variations and modifications can bemade on the aforementioned structure without departing from the conceptsof the present invention, and further it is to be understood that suchconcepts are intended to be covered by the following claims unless theseclaims by their language expressly state otherwise.

We claim:
 1. A back construction for a seating unit comprising: aflexible back panel configured to support a seated user's torso; and abladder attached to the flexible back panel so that when the bladderexpands in one direction and simultaneously shortens in a differentdirection, the back panel is flexed to a different shape.
 2. The backconstruction defined in claim 1, wherein the bladder is elongated, andwherein the different direction that shortens extends parallel a lengthof the elongated bladder.
 3. The back construction defined in claim 2,wherein the one dimension is parallel a thickness direction.
 4. The backconstruction defined in claim 3, wherein the length extends in avertical direction.
 5. The back construction defined in claim 1, whereinthe bladder includes multiple pleats that extend in a directionperpendicular to the different direction.
 6. The back constructiondefined in claim 5, wherein the pleats extend horizontally.
 7. The backconstruction defined in claim 1, including a fluid pump operablyconnected to the bladder.
 8. The back construction defined in claim 1,wherein the back panel includes a lumbar section that is flexible. 9.The back construction defined in claim 8, wherein the back panelincludes a stiff top section and a stiff bottom section connectedtogether by the lumbar section.
 10. The back construction defined inclaim 9, wherein the lumbar section includes vertically-extending sidestrips that flex, and includes horizontally extending strips that extendbetween the side strips.
 11. The back construction defined in claim 1,wherein the bladder extends vertically from top to bottom of the backshell, but extends only partially horizontally across the back shell.12. The back construction defined in claim 1, wherein the bladder isremovably attached to the back shell.
 13. The back construction definedin claim 12, including a cover assembly having a sock top shaped toslide onto and engage a top of the back shell.
 14. The back constructiondefined in claim 13, wherein the cover assembly includes a releasablebottom connector shaped to releasably engage a bottom of the back shell.15. The back construction defined in claim 1, including a cover assemblywith angled side edges extending non-parallel to side edges of backshell, the cover assembly being attached to the back shell andincorporating the bladder.
 16. The back construction defined in claim 1,wherein the bladder is riveted to the back shell.
 17. The backconstruction defined in claim 1, wherein the bladder includes multiplelayers, at least one structural layer being flexible but non-stretchableand providing strength, and at least one elastic layer being flexibleand air-impermeable to provide an air-receiving cavity.
 18. The backconstruction defined in claim 17, wherein the at least one structurallayer includes nylon, and the at least one elastic layer includesurethane.
 19. The back construction defined in claim 1, including an airpump operably connected to the bladder.
 20. A back construction for aseating unit comprising: a rigid back frame; a flexible back panelattached to and supported by the back frame at spaced-apart points; anda constrictable energy mechanism operably coupled to the flexible backpanel at spaced-apart locations so that, when the energy mechanism isenergized and constricts, the back panel is flexed to a different shape.21. The back construction defined in claim 20, wherein the back panel isslidably attached to the back frame at a bottom location.
 22. The backconstruction defined in claim 20, wherein the energy mechanism includesan inflatable bladder.
 23. The back construction defined in claim 22,wherein the bladder includes transverse pleats subdividing a length ofthe bladder into a plurality of sub-compartments.
 24. The backconstruction defined in claim 20, wherein the back panel includes afront surface, and the energy mechanism is laid on and against the frontsurface.
 25. A shape-changeable component for a furniture unitcomprising: a flexible plastic panel having a curvilinear surface; aninflatable member operably attached to the plastic panel and lying onthe curvilinear surface so that when the inflatable member expands inone direction and simultaneously shortens in a different direction, theplastic panel is flexed to a different shape.
 26. The component definedin claim 25, wherein the plastic panel forms a seating unit usable for aback of an automobile seat.